KVM: Cache pdptrs

Instead of reloading the pdptrs on every entry and exit (vmcs writes on vmx,
guest memory access on svm) extract them on demand.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 18 insertions, 4 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 752465f98bfd..d726dec69529 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -161,6 +161,8 @@ static struct kvm_vmx_segment_field {
         VMX_SEGMENT_FIELD(LDTR),
 };
 
+static void ept_save_pdptrs(struct kvm_vcpu *vcpu);
+
 /*
  * Keep MSR_K6_STAR at the end, as setup_msrs() will try to optimize it
  * away by decrementing the array size.
@@ -1047,6 +1049,10 @@ static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
         case VCPU_REGS_RIP:
                 vcpu->arch.regs[VCPU_REGS_RIP] = vmcs_readl(GUEST_RIP);
                 break;
+        case VCPU_EXREG_PDPTR:
+                if (enable_ept)
+                        ept_save_pdptrs(vcpu);
+                break;
         default:
                 break;
         }
@@ -1546,6 +1552,10 @@ static void vmx_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)
 
 static void ept_load_pdptrs(struct kvm_vcpu *vcpu)
 {
+        if (!test_bit(VCPU_EXREG_PDPTR,
+                      (unsigned long *)&vcpu->arch.regs_dirty))
+                return;
+
         if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
                 vmcs_write64(GUEST_PDPTR0, vcpu->arch.pdptrs[0]);
                 vmcs_write64(GUEST_PDPTR1, vcpu->arch.pdptrs[1]);
@@ -1562,6 +1572,11 @@ static void ept_save_pdptrs(struct kvm_vcpu *vcpu)
                 vcpu->arch.pdptrs[2] = vmcs_read64(GUEST_PDPTR2);
                 vcpu->arch.pdptrs[3] = vmcs_read64(GUEST_PDPTR3);
         }
+
+        __set_bit(VCPU_EXREG_PDPTR,
+                  (unsigned long *)&vcpu->arch.regs_avail);
+        __set_bit(VCPU_EXREG_PDPTR,
+                  (unsigned long *)&vcpu->arch.regs_dirty);
 }
 
 static void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4);
@@ -3255,10 +3270,8 @@ static int vmx_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 
         /* Access CR3 don't cause VMExit in paging mode, so we need
          * to sync with guest real CR3. */
-        if (enable_ept && is_paging(vcpu)) {
+        if (enable_ept && is_paging(vcpu))
                 vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
-                ept_save_pdptrs(vcpu);
-        }
 
         if (unlikely(vmx->fail)) {
                 kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;
@@ -3567,7 +3580,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 #endif
               );
 
-        vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
+        vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP)
+                                  | (1 << VCPU_EXREG_PDPTR));
         vcpu->arch.regs_dirty = 0;
 
         get_debugreg(vcpu->arch.dr6, 6);